Routers are used to remove material from a workpiece for decorative or functional purposes. In particular, routers may be useful in performing cabinetwork, cutting grooves in the surface or edges of a material, and applying a decorative border to a material through fluting or beading. In general, there are two types of routers: standard base routers and plunge base routers. Both types of routers include an electric motor having a rotating output shaft mounted vertically within a housing. The motor shaft terminates with a chuck, clamp, or collet for interchangeably securing a cutting tool, referred to as a router bit, to the shaft. Rotation of the shaft results in rotation of the router bit. Standard base routers and plunge base routers exhibit structural differences that affect the method by which the routers are operated.
Standard base routers include a motor unit coupled to a base having a carriage, two opposing handles, and a substantially planar work engaging surface. The carriage is connected to the top of the work engaging surface. The handles are connected to the carriage and/or the top surface of the work engaging surface. A router bit, coupled to the motor unit, is configured to extend through an opening in the work engaging surface. The distance the router bit extends from the work engaging surface is adjustable depending on the position of the motor unit relative to the carriage. In particular, the carriage may include a plurality of different positions in which the motor unit may be locked. The plurality of positions enables a user to make grooves or cuts of a particular depth, depending on which position is selected. In general, a user operates a standard base router by precisely guiding the rotating router bit around the edges or surface of a workpiece, thereby causing the rotating bit to cut and remove portions of the workpiece at a fixed and predetermined depth.
Plunge base routers include a carriage, two opposing handles, a substantially planar work engaging surface provided on a base plate, and two plunge posts. The plunge posts extend perpendicularly from the base plate and extend into channels formed in the carriage. The carriage is configured to house an electric motor. The rotating shaft of the electric motor extends downward from the carriage toward the base plate. The opposing handles are connected to opposite sides of the carriage. Biasing members are configured to bias the carriage in an upward direction away from the base plate so that the motor shaft and the router bit, if one is attached, are positioned above the base plate, out of contact with a workpiece. A user may apply downward pressure upon the opposing handles, to slide the carriage down the plunge posts toward the workpiece until the router bit extends below the base plate by a predetermined distance. Thus, the term “plunge” refers to the ability of a plunge base router to direct a router bit into contact with a workpiece from the upper position in which the router maintains the rotating router bit above the workpiece, to the lower position in which the router bit is forced into contact with the workpiece. Upon releasing the downward pressure on the handles, the biasing system forces the carriage to slide up the plunge posts to the upper position, thereby removing the router bit from contact with the workpiece.
Some routers, referred to as modular or combination routers, are configured to have a motor unit that may be removably connected to the carriage of a plunge base or the carriage of a standard base. A user may select the plunge base or the standard base depending upon the task to be performed with the router. In particular, a standard base router may be most useful in making cuts or grooves along the outer edges of a workpiece, while a plunge base router may be most useful in making cuts or grooves in the interior surface of a workpiece.
After selecting a base unit, a user should secure the motor unit to the carriage of the desired base unit. Accordingly, base unit carriages include a fastener to secure the motor unit to the carriage. For instance, the base unit may include a fastener having an adjustment mechanism that increases or decreases the amount of force with which the fastener grips the motor unit. However, some users may find the process of adjusting the fastening force inconvenient. For example, with past fasteners there was no way to set the fastening force accurately without employing a trial and error approach. Specifically, a user had to open the fastener, choose a fastener force setting, insert a motor unit, and test the fit. If the fit was too tight or too loose the user had to open the fastener, remove the motor unit from the base unit, and readjust the fastening force until an acceptable fastening force was achieved. Thus, the fastening force adjustment process was laborious, time consuming, and reliant upon the skill and judgment of the user adjusting the fastener. Accordingly, some users may incorrectly adjust the fastening force of past fasteners. For instance, some users may adjust the fastener to apply a larger than necessary fastening force to the motor unit, which could damage the fastening unit and/or the motor unit. While other users may adjust the fastener to apply too loose a fastening force to the motor unit, which might permit the motor unit to rattle or vibrate within the base, resulting in an imprecise cut or groove.
In view of the foregoing, it would be advantageous to provide a combination router having a base with a clamp for securing the motor unit to the base unit. It would be further advantageous if the clamp delivered an adjustable force upon the motor unit. It would be still further advantageous to provide a clamp that could apply a predetermined fastening force to the motor unit. Thus, an improved combination router and motor clamp are possible.